Studies of NRIM Continuous Steelmaking Process

Abstract

The fundamental aspect q! the development of the NRIM multi-stage trough type continuous steelmaking process and the results of its recent operations are presented in this jJaper. Though the scale of the plant used was small (7.8 tlhr in hot metal flow rate), a suitable sejJaration of the steelmaking reactions to each stage of the continuous steelmaking furna ce and the know-how qf its ojJeration were satiifactorily obtained. As the result of the separation, that is, silicon and phosphorus were mostly removed in the first stage so that the final carbon level was controlled mainly in the second stage, the p roduct with phosphorus as low as 0.005% (dephosjJhoriz ation rate 96%) was obtained with comparable amount of lime to that of the conventional batch type steelmaking processes. The industrializ ation of this process is confirmed to be feasible.

Historical overview on the development of converter steelmaking from Bessemer to modern practices and future outlook

“…1971; Eketorp 1971; Goss and Blough 1971; Nakagawa et al. 1971; Worner and Baker 1971). The French process was developed at IRSID research station in 1960–70s (Berthet et al 1971).…”

“…In a Japanese NRIM process, steel ran through a multi-stage, cascade type furnace by gravity flow (Nakagawa et al. 1971). Electromagnetic transportation of steel was applied to achieve counter current flow for decarburisation under oxygen top-blow in a tilted runner (Steinmetz and Kuhn 1971).…”

“…The idea was awaken in 1960s by several research groups e.g. in France, Australia, U.K., U.S. and Japan (Davies et al 1967;Rhydderch 1967;Berthet et al 1971;Eketorp 1971;Goss and Blough 1971;Nakagawa et al 1971;Worner and Baker 1971). The French process was developed at IRSID research station in 1960-70s (Berthet et al 1971).…”

“…The WORCRA process, initiated in Australia at Broken Hill and tested at Mefos Lulea in early 1970s, used counter current metal/slag flows in a long L-shape launder for refining (Worner and Baker 1971;Brooks, Ross and Worner 1997). In a Japanese NRIM process, steel ran through a multi-stage, cascade type furnace by gravity flow (Nakagawa et al 1971). Electromagnetic transportation of steel was applied to achieve counter current flow for decarburisation under oxygen top-blow in a tilted runner (Steinmetz and Kuhn 1971).…”